chore: close issues 0007a-e, update feature flag and sources manifest

Enable dag-engine feature flag, document dagu as analyzed (GPL-3.0,
no code extracted), move all 0007 issues to completed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

dev/issues/README.md

@@ -8,9 +8,9 @@
 | 0004 | Jupyter discover multiple instances | completado | — | feature | — |
 | 0005 | Jupyter write batch | completado | — | feature | — |
 | 0006 | Jupyter exec outputs keyerror | completado | — | bugfix | — |
-| **0007a** | **DAG engine: core (parse, validate, topo sort)** | pendiente | alta | feature | 0007b-e |
-| **0007b** | **DAG engine: process manager (spawn, wait, kill)** | pendiente | alta | feature | 0007e |
-| **0007c** | **DAG engine: execution store (SQLite)** | pendiente | alta | feature | 0007e |
-| **0007d** | **DAG engine: scheduler (cron parser, ticker)** | pendiente | media | feature | 0007e |
-| **0007e** | **DAG engine: app CLI que reemplaza Dagu** | pendiente | alta | feature | — |
+| [0007a](completed/0007a-dag-core.md) | DAG engine: core (parse, validate, topo sort) | completado | alta | feature | 0007b-e |
+| [0007b](completed/0007b-process-manager.md) | DAG engine: process manager (spawn, wait, kill) | completado | alta | feature | 0007e |
+| [0007c](completed/0007c-execution-store.md) | DAG engine: execution store (SQLite) | completado | alta | feature | 0007e |
+| [0007d](completed/0007d-scheduler.md) | DAG engine: scheduler (cron match) | completado | media | feature | 0007e |
+| [0007e](completed/0007e-dag-executor-app.md) | DAG engine: CLI + web app que reemplaza Dagu | completado | alta | feature | — |
 | **0008** | **SQLite API Web** | pendiente | alta | feature | — |